/*************************************************************************** * Copyright (c) 2024 Microsoft Corporation * Copyright (c) 2026-present Eclipse ThreadX contributors * * This program and the accompanying materials are made available under the * terms of the MIT License which is available at * https://opensource.org/licenses/MIT. * * SPDX-License-Identifier: MIT **************************************************************************/ /**************************************************************************/ /**************************************************************************/ /** */ /** ThreadX Component */ /** */ /** Timer */ /** */ /**************************************************************************/ /**************************************************************************/ /* #define TX_SOURCE_CODE */ /* Include necessary system files. */ /* #include "tx_api.h" */ /* #include "tx_timer.h" */ /* #include "tx_thread.h" */ /* Define Assembly language external references... */ .global _tx_timer_time_slice .global _tx_timer_system_clock .global _tx_timer_current_ptr .global _tx_timer_list_start .global _tx_timer_list_end .global _tx_timer_expired_time_slice .global _tx_timer_expired .global _tx_thread_time_slice .global _tx_timer_expiration_process #ifdef TX_THUMB_MODE .thumb #else .arm #endif .text .eabi_attribute Tag_ABI_align_preserved, 1 /**************************************************************************/ /* */ /* FUNCTION RELEASE */ /* */ /* _tx_timer_interrupt Cortex-R4/AC6 */ /* 6.1 */ /* AUTHOR */ /* */ /* William E. Lamie, Microsoft Corporation */ /* */ /* DESCRIPTION */ /* */ /* This function processes the hardware timer interrupt. This */ /* processing includes incrementing the system clock and checking for */ /* time slice and/or timer expiration. If either is found, the */ /* interrupt context save/restore functions are called along with the */ /* expiration functions. */ /* */ /* INPUT */ /* */ /* None */ /* */ /* OUTPUT */ /* */ /* None */ /* */ /* CALLS */ /* */ /* _tx_timer_expiration_process Timer expiration processing */ /* _tx_thread_time_slice Time slice interrupted thread */ /* */ /* CALLED BY */ /* */ /* interrupt vector */ /* */ /**************************************************************************/ /* VOID _tx_timer_interrupt(VOID) */ /* { */ .global _tx_timer_interrupt .type _tx_timer_interrupt, "function" _tx_timer_interrupt: /* Upon entry to this routine, it is assumed that context save has already been called, and therefore the compiler scratch registers are available for use. */ /* Increment the system clock. */ /* _tx_timer_system_clock++; */ LDR r1, =_tx_timer_system_clock // Pickup address of system clock LDR r0, [r1, #0] // Pickup system clock ADD r0, r0, #1 // Increment system clock STR r0, [r1, #0] // Store new system clock /* Test for time-slice expiration. */ /* if (_tx_timer_time_slice) */ /* { */ LDR r3, =_tx_timer_time_slice // Pickup address of time-slice LDR r2, [r3, #0] // Pickup time-slice CMP r2, #0 // Is it non-active? BEQ __tx_timer_no_time_slice // Yes, skip time-slice processing /* Decrement the time_slice. */ /* _tx_timer_time_slice--; */ SUB r2, r2, #1 // Decrement the time-slice STR r2, [r3, #0] // Store new time-slice value /* Check for expiration. */ /* if (__tx_timer_time_slice == 0) */ CMP r2, #0 // Has it expired? BNE __tx_timer_no_time_slice // No, skip expiration processing /* Set the time-slice expired flag. */ /* _tx_timer_expired_time_slice = TX_TRUE; */ LDR r3, =_tx_timer_expired_time_slice // Pickup address of expired flag MOV r0, #1 // Build expired value STR r0, [r3, #0] // Set time-slice expiration flag /* } */ __tx_timer_no_time_slice: /* Test for timer expiration. */ /* if (*_tx_timer_current_ptr) */ /* { */ LDR r1, =_tx_timer_current_ptr // Pickup current timer pointer addr LDR r0, [r1, #0] // Pickup current timer LDR r2, [r0, #0] // Pickup timer list entry CMP r2, #0 // Is there anything in the list? BEQ __tx_timer_no_timer // No, just increment the timer /* Set expiration flag. */ /* _tx_timer_expired = TX_TRUE; */ LDR r3, =_tx_timer_expired // Pickup expiration flag address MOV r2, #1 // Build expired value STR r2, [r3, #0] // Set expired flag B __tx_timer_done // Finished timer processing /* } */ /* else */ /* { */ __tx_timer_no_timer: /* No timer expired, increment the timer pointer. */ /* _tx_timer_current_ptr++; */ ADD r0, r0, #4 // Move to next timer /* Check for wrap-around. */ /* if (_tx_timer_current_ptr == _tx_timer_list_end) */ LDR r3, =_tx_timer_list_end // Pickup addr of timer list end LDR r2, [r3, #0] // Pickup list end CMP r0, r2 // Are we at list end? BNE __tx_timer_skip_wrap // No, skip wrap-around logic /* Wrap to beginning of list. */ /* _tx_timer_current_ptr = _tx_timer_list_start; */ LDR r3, =_tx_timer_list_start // Pickup addr of timer list start LDR r0, [r3, #0] // Set current pointer to list start __tx_timer_skip_wrap: STR r0, [r1, #0] // Store new current timer pointer /* } */ __tx_timer_done: /* See if anything has expired. */ /* if ((_tx_timer_expired_time_slice) (_tx_timer_expired)) */ /* { */ LDR r3, =_tx_timer_expired_time_slice // Pickup addr of expired flag LDR r2, [r3, #0] // Pickup time-slice expired flag CMP r2, #0 // Did a time-slice expire? BNE __tx_something_expired // If non-zero, time-slice expired LDR r1, =_tx_timer_expired // Pickup addr of other expired flag LDR r0, [r1, #0] // Pickup timer expired flag CMP r0, #0 // Did a timer expire? BEQ __tx_timer_nothing_expired // No, nothing expired __tx_something_expired: STMDB sp!, {r0, lr} // Save the lr register on the stack // and save r0 just to keep 8-byte alignment /* Did a timer expire? */ /* if (_tx_timer_expired) */ /* { */ LDR r1, =_tx_timer_expired // Pickup addr of expired flag LDR r0, [r1, #0] // Pickup timer expired flag CMP r0, #0 // Check for timer expiration BEQ __tx_timer_dont_activate // If not set, skip timer activation /* Process timer expiration. */ /* _tx_timer_expiration_process(); */ BL _tx_timer_expiration_process // Call the timer expiration handling routine /* } */ __tx_timer_dont_activate: /* Did time slice expire? */ /* if (_tx_timer_expired_time_slice) */ /* { */ LDR r3, =_tx_timer_expired_time_slice // Pickup addr of time-slice expired LDR r2, [r3, #0] // Pickup the actual flag CMP r2, #0 // See if the flag is set BEQ __tx_timer_not_ts_expiration // No, skip time-slice processing /* Time slice interrupted thread. */ /* _tx_thread_time_slice(); */ BL _tx_thread_time_slice // Call time-slice processing /* } */ __tx_timer_not_ts_expiration: LDMIA sp!, {r0, lr} // Recover lr register (r0 is just there for // the 8-byte stack alignment /* } */ __tx_timer_nothing_expired: BX lr // Return to caller /* } */